We used a Queen Size mattress at the ASMovies last August. Being that we were three 20-something ladies on the trip, we decided we would want the extra room and not have to snuggle up every night
We moved the table and chairs into the closet area (we never use it anyhow) and put the air bed at the bottom of the bed near the door. There was no way to walk around the air mattress or bed closest to the door (just over). However there was a clear path on the other side bed to make it to the bathroom and such. Then during the day, we just leaned the bed up against the wall, so that we had plenty of room to walk around.